Merge bitcoin#29718: Correct '-dbcache' to '-prune'

416b9d9 correct '-dbcache' to '-prune' (Ben Westgate)

Pull request description:

  This looks like a typo, '-prune' is doubled not the '-dbcache' by my understanding.

ACKs for top commit:
  Sjors:
    ACK 416b9d9
  fjahr:
    ACK 416b9d9

Tree-SHA512: d954a8976f6e43e0af9bc2ba89fec1a1ccc90483cc005af3d2810379bd6bea7dbd87766af71c2a45b3d751a3f682f0f67a4525ec350bf6163bc4bb88fab6e4cb

Author: fanquake

doc/design/assumeutxo.md

@@ -16,7 +16,7 @@ load it.
 A pruned node can load a snapshot. To save space, it's possible to delete the
 snapshot file as soon as `loadtxoutset` finishes.
 
-The minimum `-dbcache` setting is 550 MiB, but this functionality ignores that
+The minimum `-prune` setting is 550 MiB, but this functionality ignores that
 minimum and uses at least 1100 MiB.
 
 As the background sync continues there will be temporarily two chainstate